The Transonic Wind Tunnel Göttingen (TWG) - DNW
Transcript of The Transonic Wind Tunnel Göttingen (TWG) - DNW
The Transonic Wind Tunnel Göttingen (TWG)
www.dnw.aero
exchangeable test sections (1 m × 1 m):
flexible Laval test section (supersonic)
perforated test section (sub-, transonic)
adaptive test section (subsonic)
axial compressor (2 × 4 stages)
46.5 m
screens
flowstraightener
cooler
motor (12 MW)
Figure 1
The TWG is a closed circuit, ‘Göttingen Type’, wind tunnel for
sub-, trans-, and supersonic flow research and development tests
at air, space, and surface vehicle configurations and components.
Total pressure 0.3 ÷ 1.5 × 105 Pa
Dynamic pressure (max) 0.53 × 105 Pa
Temperature range 293 ÷ 315 K
The eight-stage axial compressor with an
electrical power supply of 12 MW allows for
continuous flow in the test section. An auxiliary
radial compressor with 3 MW is used as a
suction plant, in the case that the test section
with perforated walls is installed in the plenum
chamber. The whole tunnel can be pressurized or
evacuated, thus enabling variation of stagnation
pressure and Reynolds number independently
of the Mach number. An efficient air drying
system guarantees humidity levels low enough
to avoid condensation and flow disturbance in
the whole speed range. The water cooling system
is designed to keep the tunnel temperature
constant in the specified range.
Since its commissioning in 1964 the TWG has
been repeatedly upgraded. Major modifications
have provided improved flow quality, extended
test spectrum, and increased productivity in
a new concept with three exchangeable test
sections, exchangeable model supports, and
excellent model access. The test section, model
support, and model change logistics are enabled
by an air cushion transport system. The plenum
chamber can be accessed by a 10 m wide sliding
door to the plenum. Inside the plenum, for free
model access, the tunnel circuit can be opened by
axially moving the contraction nozzle, together
with the test section, several meters into the
settling chamber. The tunnel components,
Key Technical ParametersMach number
Adaptive walls 0.3 ÷ 0.9
Perforated walls 0.3 ÷ 1.2
Laval nozzle 1.3 ÷ 2.2
Reynolds number
(max, lref=0.1 m) 1.8 × 106
Test section size 1 m × 1 m × 4.5 m
Contraction 16:1
Drive power 12 MW
Figure 2
Plenum (sliding door and test
section opened).
Figure 3
TWG simulation range.
the test runs, and the measurement and data
acquisition are automatically controlled by an
integrated hard- and software system.
Simulation RangeThe Mach number range covered by the three
test sections of the TWG is 0.3 ≤ M ≤ 2.2.
Between M=0.9 and 1.2 the flow simulation needs
additional suction through the perforated walls
and out of the plenum with re-injection behind the
flexible diffuser. To vary the Reynolds number, the
total pressure of the test gas can be varied in the
range 0.3 ÷1.5 ×105 Pa. This results in maximum
Reynolds numbers of 1.8×106 based on a 3D model
reference length of 0.1 m or 7.2×106 based on a
maximum airfoil model chord length of 0.4 m.
Test SectionsThree exchangeable test sections with a cross
section of 1 m × 1 m and a length of 4.5 m
are designed with emphasis on different Mach
number ranges.
The Transonic Wind Tunnel Göttingen (TWG)
Figure 5
Dynamic half model
support on the support
portal.
Figure 4
Model installation between
side walls.
The transonic test section with conventionally
perforated walls (6% open, 60° inclined,
Mdesign = 1.05) can be operated with different
suction rates in the range 0.3 ≤ M ≤ 1.2.
The second test section has flexible upper and
lower walls allowing a 2D adaptation to the
flow field. Thus, compared to conventional test
sections, the wall interference is reduced and/or
larger models can be used in the range
0.3 ≤ M ≤ 0.9. Using wall pressure distribution
measurements a single-step algorithm, based
on Cauchy´s integral formula for airfoil (2D) tests
and on the Wedemeyer-Lamarche method for
3D models respectively, is applied to the
adaptation. In case of 3D model testing the
small residual wall interferences are calculated
by Green´s integral formula and used for final
correction.
The supersonic test section is a conventional
Laval nozzle with flexible top and bottom walls
calibrated for discrete Mach numbers in the range
1.3 ≤ M ≤ 2.2.
Model SupportsThe flexibility of the TWG, especially the modular
construction of the adaptive and the perforated
test section, provides for the possibility to realize
a variety of different model supports, depending
on the special test requirements. Two classes of
model supports are used.
Model Installation on or between the Side WallsAirfoils are fixed between synchronized
slewing rings on both sides of a portal support,
surrounding the adaptive or the perforated walls
test section. The walls are closed by turn tables.
The remotely controlled pitch angle covers ± 15°,
The Transonic Wind Tunnel Göttingen (TWG)
Figure 6
PSP coated model on a cranked
roll adapter (used for direct sideslip
simulation).
Figure 7
Elastic wing model on dynamic
half model support.
Test Sections and Model Supports
which can be shifted by an offset installation.
This support is placed upstream of the standard
3D model position in order to provide a better
wake simulation, especially for 2D models.
The portal support is designed to support half
models or side sting mounted models and to take
up hydraulically driven pitch and heave oscillation
and flutter test beds. This and other dynamic
test beds, specifically adapted to the TWG, are
operated by the DLR Institute of Aeroelasticity at
Göttingen. In the supersonic test section (Laval
nozzle) remotely controlled, synchronized half
model supports can be installed in the side wall
window frames.
Model Installation on the Downstream Sword3D models are typically are supported on the
sword, which can be rotated by = ± 17° and
traversed vertically by ∆ z= ± 100 mm and axially
by ∆ x=250mm. The center of rotation is 1500
mm in front of the sword leading edge. The
sword, with models installed, can stay in the
tunnel circuit, while the three test sections are
exchanged. A special air cushion system allows
to move the sword with the installed model
out of the tunnel to a parking position in the
wind tunnel hall. The integrated roll unit covers
the range = ±100°. Model support stings
can be flanged at arbitrary angles. The whole
support system is designed to bear the following
maximum loads acting in the rotational center
of the sword (corresponding to the strongest
standard internal strain gauge balance):
Forces:
X ≤ 2000 N
Y ≤ 4000 N
Z ≤ 8000 N
Higher angles of incidence are realized by using
adapters with appropriate crank angles. Some of
them have a remote-controlled roll drive of their
own and thus, in combination with the main roll
device, allow direct sideslip simulation.
Several experiments with models rapidly rolling
with the rear sting were realized with the help of
specially designed fast rolling units, flanged to
the sword. The rolling motion is either free (only
aerodynamically driven) or forced by an electrical
motor (constant, oscillatory, or transient).
A special sword with a hydraulically driven pitch
mechanism is available to examine fast pitch
maneuvers.
Moments:
L ≤ 500 Nm
M ≤ 500 Nm
N ≤ 500 Nm
Figure 10
Measurement of loads on
model components with
Pressure Sensitive Paint
(PSP).
Special Simulation ServicesDNW-TWG offers flexible solutions for special
simulation tasks, some with support of DLR-
Institutes AS and AE:
• High precision Mach number tuning in steps
of 0.001
• Continuous sweep measurement of pitch
(0.5°/sec)
• Direct sideslip angle simulation (span direction
horizontal)
• Efficient systems for suction and blowing
(heated air) through model or tunnel walls
• Air intake simulation, drag bookkeeping by
duct flow measurement
• Forced and free pitch and heave oscillation and
flutter simulation of 2D and half-models
• Dynamically scaled models
• Rapidly rolling models (constant speed,
oscillation, transient)
• Dynamically remote controlled control surfaces
• Upper and lower tunnel wall adaptation for
0.3 ≤ M ≤ 0.9
• Weapon bay aero-acoustics
Measurement Techniques and EquipmentThe DNW policy is to keep the measurement
equipment on a high standard. Sharing of
equipment between the DNW wind tunnel sites
is a common practice. This allows meeting a large
range of customer requirements. In addition,
the available support on site by the German
Aerospace Center DLR (Institute of Aerodynamics
and Flow Technology Göttingen and Institute
of Aeroelasticity) gives DNW access to a lot
of particularly suitable and, for the purpose of
development and improvement, most advanced
measurement and simulation techniques. These
techniques are partly developed in the TWG and
therefore the installation of these techniques at
Figure 8
Missile model with trough
flow ducts (throttle cone
behind tail nozzle).
Figure 9
Schlieren picture of space
vehicle.
The Transonic Wind Tunnel Göttingen (TWG)
Simulation Services and Measurement Techniques
the wind tunnel is well prepared and includes
the integration in the TWG data acquisition
system.
Forces and MomentsFor the measurement of static total forces and
moments a wide range of internal strain gauge
balances of different size and load range is
available (most of them manufactured by TASK
Able and the follow up company Aerophysics
Research Instruments). Additional balances are
used for half-model tests and for forces on model
parts, respectively.
For unsteady force and moment measurements
special piezo-electric balances (owned by
DLR) can easily be operated in the TWG
environment.
PressuresFor static pressure measurements PSI©
Scanning Systems are operated. These allow
the measurement of several hundred pressures
accurately and fast, by using temperature
compensated electronic pressure scanning
modules. For highly accurate pressure
measurement differential pressure transducers are
available. For the evaluation of dynamic pressures
a large number of Endevco© and Kulite© pressure
transducers can be operated.
The combined analysis based on profile pressures
and wake rake pressures allows lift, drag and
pitching moment measurement.
Optical Measurement TechniquesA Schlieren system can provide black-and-white
as well as colored Schlieren images. The images
can either be recorded as single images with high
resolution or as film with reduced resolution.
Flow visualization on the model surface is realized
with colored oil film technique. The laminar-
turbulent transition can be observed both with
Temperature Sensitive Paint (TSP) or the infrared
technique (owned by DLR).
The pressure sensitive paint (PSP) gives a more
detailed and quantitative view on the surface
pressure distribution. In addition to this, loads on
particular model parts can be calculated.
In cooperation with the DLR several additional
techniques can be provided:
• flow field measurement: Particle Image
Velocimetry (PIV), Background Oriented
Schlieren (BOS) and the Laser Light Sheet
(LLS) technique
• deformation detection: the Moiré technique
or the Image Pattern Correlation (IPC)
technique
• model positioning: Optical Position Detection
System (Posi).
Dynamic Data AcquisitionFor dynamic data analysis a high precision data
acquisition system, consisting of more than
hundred channels, synchronized with the wind
tunnel or model control system and connected to
the static data acquisition system is available.
DLR operates some optical measurement
techniques (PIV, PSP, BOS, IPC) as dynamic
systems for evaluating unsteady flow conditions
or model motion.
Wind Tunnels Operated by DNW
HST, SSTAnthony Fokkerweg 21059 CM AmsterdamThe Netherlands
Contact: G.H. HegenPhone: +31 527 24 8519Fax: +31 527 24 8582E-mail: [email protected]
TWG, HDG, KRG, RWGBunsenstraße 1037073 GöttingenGermany
Contact: K.-W. BockPhone: +49 551 709 2828Fax: +49 551 709 2888E-mail: [email protected]
LLF, LST, ECFVoorsterweg 318316 PR MarknesseThe Netherlands
Contact: G.H. HegenPhone: +31 527 24 8519Fax: +31 527 24 8582E-mail: [email protected]
NWBLilienthalplatz 738108 BraunschweigGermany
Contact: A. BergmannPhone: +49 531 295 2450Fax: +49 532 295 2829E-mail: [email protected]
General Inquiries
Henri VosBusiness Development
Mobile: +31 6 12 97 52 82Phone: +31 527 24 85 05Fax: +31 527 24 85 82E-mail: [email protected]
KKKLinder Höhe51147 KölnGermany
Contact: R. RebstockPhone: +49 2203 601 3700Fax: +49 2203 695 961E-mail: [email protected]